This invention is a stent and stent delivery system suited for the noninvasive treatment of aneurysms, diseased blood vessels, and other bodily lumen. Unlike most known stents, the stents described herein are able to be positioned in situ with one or more wires attached to at least one location at the distal end of the stent and/or at least one location at the proximal end of the stent.
This invention is an stent and stent delivery system which may be used within various portions of the body""s vasculature. In general, stents are prosthetic devices which may be introduced into a body cavity such as the lumen of a blood vessel or in some other difficult to access location. Stents are particularly useful for permanently widening a vessel which is either in a narrowed condition or has been damaged by aneurysm. Stents are typically introduced into the vasculature or other body cavity by the use of a catheter. Stents are usually tubular bodies made up of radially stiff shapes (for example circles) connected together to form the tubular shape.
Currently, the majority of stents are delivered to the target site as radially expandable preformed structures. In other words, only the diameter of the stent may be increased or decreased once properly positioned in the region where they are to be left. For instance, WO 92/02,246, owned by Numed, Inc., shows a radially expandable stent made from fine wire formed into a serpentine ribbon wound into a cylindrical shape for introduction into a body vessel. The stent is placed within the vessel over a balloon which, when expanded, expands the stent in a radial fashion to support the wall of the vessel in the expanded configuration. This stent is said to be useful in the transluminar implantation of a stent for use in coronary angioplasty to prevent restenosis.
Other disclosures of expandable intraluminal stents involving radially expanding wire mesh include U.S. Pat. No. 4,776,337, to Palmaz. The patent shows a tubular member which may be made of a variety of different things supported by a gridlike collection of metal or plastic wires. U.S. Pat. No. 4,800,882, to Gianturco, shows a wire stent made of a number of curved sections that are formed into a generally circular configuration. U.S. Pat. No. 6,007,573 shows a rolled sheet stent releasably mounted on the distal tip of the deployment catheter. U.S. Pat. No. 6,063,101 shows a balloon expandable stent which includes a hollow wire through which drugs and the like are delivered to the stent itself. The hollow wire is detached after drug deliver using ultrasonic energy.
Stents delivered to a restricted coronary artery, expanded to a larger diameter as by a balloon catheter, and left in place in the artery at the site of a dilated lesion are shown in U.S. Pat. No. 4,740,207 to Kreamer; U.S. Pat. No. 5,007,926 to Derbyshire; U.S. Pat. No. 4,733,665 to Palmaz; U.S. Pat. No. 5,026,377 to Burton et al.; U.S. Pat. No. 5,158,548 to Lau et al.; U.S. Pat. No. 5,242,399 to Lau et al.; U.S. Pat. No. 5,344,426 to Lau et al.; U.S. Pat. No. 5,415,664 to Pinchuk; U.S. Pat. No. 5,453,090 to Martinez et al.; U.S. Pat. No. 4,950,227 to Savin; U.S. Pat. No. 5,403,341 to Solar; U.S. Pat. No. 5,108,416 to Ryan et al. and European Patent Application No. 707 837 A1 to Sheiban, all of which are incorporated herein by reference.
WO 97/48351, to the Medical University of South Carolina, discloses a multiple layered, self-forming intravascular flow modifier (IFM). Notably, at least a portion of the outer layer surrounds at least a portion of the inner layer so that at least some loops of the outer layer overlap and contact at least some loops of the inner layer. In other words, the turns making up the final configuration are necessarily overlapping and touching each other. The IFM also has a relatively high stiffness. The IFM is deployed using co-axial catheters.
None of these documents depict self-expandable or self-forming stents having a wire attached to the proximal end of the stent and/or the distal end of the stent which allow the operator to position the stent in situ. Further, none describe a self-forming stent which forms a tubular structure of turns from a substantially linear configuration upon deployment and in which the turns making up the tubular structure do not contact each other. Thus, the present invention is particularly directed to stents which can be configured upon deployment and delivery systems which facilitate delivery thereof.
Thus, this invention includes novel stents, stent delivery systems and methods of using these stents and stent delivery systems.
In one aspect, the invention includes a self-expandable and self-forming stent device having a proximal end and a distal end and at least one detachable proximal wire connected to the proximal end or at least one detachable distal wire connected to the distal end. The stents can comprise at least one detachable proximal wire connected to the proximal end of the stent; at least one distal wire connected to the distal end of the stent; or both at least one proximal and at least one distal wire connected to the proximal and distal ends of the stent, respectively. In some embodiments, the proximal and/or distal wires are attached to more than one location of the stent. In some embodiments, one or more of the attached distal and/or proximal wires are electrolytically detachable from the stent by imposition of a current on the proximal wire. In other embodiments, one or more of the attached distal and/or proximal wires are adapted to detach from the stent using mechanical, hydraulic, ultrasonic or radio-frequency detachment mechanisms. In yet other embodiments, the stent further comprises at least one insulator between the proximal and distal wires. In other embodiments, any of the stent described herein further comprise at least one aperture through which the distal wire is threaded. Further, any of the stents described herein can further comprise a bioactive coating (e.g., a therapeutic agent). In still further embodiments, any of the stent devices described herein further comprise a sheath. The sheath can further include at least one delivery wire.
In other aspects, stents with attached proximal and/or distal wires are self-forming. In some embodiments, the self-forming stent device has a first substantially linear configuration for insertion into a restraining member and a second tubular configuration upon extrusion from the restraining member, the second tubular configuration comprising a plurality of turns, wherein the turns are not touching and further wherein the second tubular configuration has an outer diameter and at least a portion of the outer diameter conforms to the vasculature. In certain embodiments, the stent self-forms into the second tubular configuration and the restraining member comprises a deployment catheter. In other embodiments, the stent further includes at least one aperture in each turn of the secondary configuration through which the distal wire is threaded.
In other aspects, the invention includes a method of delivering any of the self-forming stents described herein to a selected site in a body cavity, the method comprising: (a) loading a substantially straightened, self-forming stent into a catheter; (b) accessing the selected site with the catheter; and (c) discharging the stent from the catheter at the selected site, wherein the stent forms a tubular configuration upon discharge. In certain embodiments, wherein step (c) comprises: (i) pushing the stent out of the catheter by applying pressure to the proximal wire while keeping the stent in the desired location by applying tension to the distal wire; and (ii) applying electrical impulses sufficient to detach the distal and proximal wires from the stent. In addition, step (c) further comprises (iii) moving the catheter. In some embodiments, the selected site is a lesion.
These and other embodiments of the subject invention will readily occur to those of skill in the art in light of the disclosure herein.